Mardu Hordechief

Raid — When Mardu Hordechief enters, if you attacked this turn, create a 1/1 white Warrior creature token.

The List

Khans of Tarkir

Raid — When Mardu Hordechief enters the battlefield, if you attacked with a creature this turn, put a 1/1 white Warrior creature token onto the battlefield.

Raid abilities care only that you attacked with a creature. It doesn’t matter how many creatures you attacked with, or which opponent or planeswalker controlled by an opponent those creatures attacked.

Raid abilities evaluate the entire turn to see if you attacked with a creature. That creature doesn’t have to still be on the battlefield. Similarly, the player or planeswalker it attacked doesn’t have to still be in the game or on the battlefield, respectively.